1. Field of the Invention
This invention relates generally to security alarms and actuating switches. More particularly the invention relates to improvements in the alarms and switches of such systems to provide reliable and effective operation, particularly in the case of cabinet security and other applications for detecting movement of an object.
2. Description of the Prior Art
Security alarms, particulary for cabinets, have been proposed whereby a switch is tripped by the opening of a door. The switch completes a circuit and thereby activates an alarm. Improvements have included a delayed alarm to allow an individual time to deactivate the system during authorized entry.
Recent improvements have included means to adapt such systems to monitor child access to cabinets. In U.S. Pat. No. 3,797,006 such a system is proposed which incorporates a time delay. A spring loaded plunger switch is connected to switch power to an electronic control for an alarm. The electronic control operates to sound the alarm after a preset time delay. More recently in U.S. Pat. No. 4,688,023 a drawer alarm was proposed which uses a pivoting switch normally held in the closed position by a compressed coil spring. When the drawer is closed, the switch is held open; but when the drawer is opened the compressed spring expands to close the circuit and sound the alarm. Notwithstanding, these prior efforts, improvements were still needed in the available operational features and reliability of such systems.